See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

This reaction is the Kolbe-Schmitt reaction, where a phenoxide salt reacts with CO2 under pressure followed by acid workup to give a hydroxybenzoic acid. Step 1 - Concept: The Kolbe-Schmitt reaction involves carboxylation of a phenoxide ion with CO2. The regioselectivity (ortho vs para) depends on the metal cation of the phenoxide salt used. Step 2 - Statement (a): When sodium phenoxide (PhONa) is used, the sodium cation coordinates with the oxygen of the phenoxide and the CO2 through a cyclic six-membered transition state, directing the carboxylate group to the ortho position. Therefore, the ortho isomer (salicylic acid) is the major product with PhONa. Statement (a) is TRUE. Step 3 - Statement (b): When potassium phenoxide (PhOK) is used, the larger potassium cation cannot form the tight cyclic ortho-directing transition state as effectively. Instead, the reaction proceeds through a less constrained pathway, and the para isomer (4-hydroxybenzoic acid) becomes the major product. Statement (b) is TRUE. Step 4 - Statement (c): The major product from PhONa is salicylic acid (2-hydroxybenzoic acid). Salicylic acid is acetylated (reacted with acetic anhydride) to produce aspirin (acetylsalicylic acid). Therefore, the product (salicylic acid) is indeed a precursor for the drug aspirin. Statement (c) is TRUE. Step 5 - Conclusion: Since all three statements (a), (b), and (c) are individually correct, option (d) 'All of these' is the correct answer. Therefore, the correct answer is D.